Utilizing polyurethanes in photoreactive polymer systems is known in the art. Generally, such systems are unsaturated acrylate or methacrylate terminated polyurethanes obtained by the reaction of hydroxyalkyl acrylate or methacrylate esters or N-metholacrylamide with isocyanate end groups in the polyurethanes and require, in addition to the polyurethane, at least one added polymerizable monomer to cause a photocrosslinking reaction.
Such prior art photoreactive systems are applied to a substrate in liquid form and, as such, cannot be effectively embossed. Coatings embossed in such a fluid state would not retain any dimensionality and would flow and level. Such coatings could only be embossed after being converted via irradiation to a cured, cross-linked, network and, as such, could not be embossed very sharply. In other photoreactive polymer systems, such as those used in imaging systems, a photoactive unsaturated side chain or a pendant substituent such as cinnamate or benzylideneacetone is required to produce the desired photocross-linking.